strings.Trim sometimes trims incorrectly

[asCii88]

Please answer these questions before submitting your issue. Thanks!

What version of Go are you using (go version)?

go1.8 windows/amd64

What operating system and processor architecture are you using (go env)?

GOARCH=amd64

What did you do?

I run this

aux := "PW/V2/C2/RQ/CMD/45465/44545"
fmt.Println(strings.Trim(aux, "PW/V2/C2/RQ/"))

Playground

What did you expect to see?

Output should be CMD/45465/44545

What did you see instead?

Output is MD/45465/44545

[cespare]

The second argument to Trim is a set of code points, not a prefix/suffix.

You probably want strings.TrimPrefix.

[asCii88]

Thank you, sorry.

Best way to get an answer on the Internet is to be wrong :)

[ianlancetaylor]

This mistake is practically a FAQ. Perhaps we can clarify the docs somehow.

[bradfitz]

The docs at least say "cutset" these days:

https://golang.org/pkg/strings/#Trim

And there's an example that says !!! Achtung! Achtung! !!! which is only more alarming when it's shouted at you verbally.

[davecheney]

I offer that people don't know what cutset means, and are left to assume that it means "fancy word for the string I want to trim off".

…

On Fri, Mar 3, 2017 at 7:57 AM, Brad Fitzpatrick ***@***.***> wrote: The docs at least say "cutset" these days: https://golang.org/pkg/strings/#Trim And there's an example that says *!!! Achtung! Achtung! !!!* which is only more alarming when it's shouted at you verbally. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#19371 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAcA0Is4U4BSvgjLR8LSOHLQwm9wV6iks5rhy1FgaJpZM4MReBm> .

[bradfitz]

Dave, totally agree. I was only saying it used to be even worse. :)

[davecheney]

No argument there, mind if I take a stab at improving it?

…

On Fri, Mar 3, 2017 at 8:31 AM, Brad Fitzpatrick ***@***.***> wrote: Dave, totally agree. I was only saying it used to be even worse. :) — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#19371 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAcA68B2ugh4SrhbYV7EJ6AKWukzXgcks5rhzU9gaJpZM4MReBm> .

[bradfitz]

🔪🔪🔪 stab away

[asCii88]

Yep, exactly. I Googled code points and I didn't even think about cutset.
I still have no idea what it does after seeing the example. I would assume it just cuts each time it finds the other string.
Then again, I was trying at first with TrimLeft, and didn't realize there was a TrimPrefix.

[zigo101]

http://www.tapirgames.com/blog/golang-unofficial-faq#trim :-)